Hi Guys, i thinks this is Tremella mesenterica, or yellow brain fungus (or Witches Butter).
It starts off yellow, but dries to quite a vibrant orange.
Seem a lot of it about this year.
Thank you very much for the info, I'll be looking into all of the species mentioned. I found it in a mixed type of woodland just next to a coppicing area (castanae sativa). It is growing on a piece of oak though.